Elements Specific to Link

<href>

A URL (either an HTTP address or a local file specification). When the parent of <Link> is a NetworkLink, <href> is a KML file. When the parent of <Link> is a Model, <href> is a COLLADA file. When the parent of <Icon> (same fields as <Link>) is an Overlay, <href> is an image. Relative URLs can be used in this tag and are evaluated relative to the enclosing KML file. See KMZ Files for details on constructing relative references in KML and KMZ files.

<refreshMode>

Specifies a time-based refresh mode, which can be one of the following:

onChange - refresh when the file is loaded and whenever the Link parameters change (the default). onInterval - refresh every n seconds (specified in <refreshInterval>).

onExpire - refresh the file when the expiration time is reached. If a fetched file has a NetworkLinkControl, the <expires> time

takes precedence over expiration times specified in HTTP headers. If no <expires> time is specified, the HTTP max-age header is used (if present). If max-age is not present, the Expires HTTP header is used (if present). (See Section RFC261b of the Hypertext Transfer Protocol - HTTP 1.1 for details on HTTP header fields.)

<refreshInterval>

Indicates to refresh the file every n seconds.

<viewRefreshMode>

Specifies how the link is refreshed when the "camera" changes. Can be one of the following:

never (default) - Ignore changes in the view. Also ignore <viewFormat> parameters, if any.

onStop - Refresh the file n seconds after movement stops, where n is specified in <viewRefreshTime>.

onRequest - Refresh the file only when the user explicitly requests it. (For example, in Google Earth, the user right-clicks and

selects Refresh in the Context menu.)

onRegion - Refresh the file when the Region becomes active. See <Region>.

<viewRefreshTime>

After camera movement stops, specifies the number of seconds to wait before refreshing the view. (See <viewRefreshMode> and onStop above.)

<viewBoundScale>

Scales the BBOX parameters before sending them to the server. A value less than 1 specifies to use less than the full view (screen). A value greater than 1 specifies to fetch an area that extends beyond the edges of the current view.

<viewFormat>

Specifies the format of the query string that is appended to the Link's <href> before the file is fetched.(If the <href> specifies a local file, this element is ignored.)

If you specify a <viewRefreshMode> of onStop and do not include the <viewFormat> tag in the file, the following information is automatically appended to the query string:

BBOX=[bboxWest],[bboxSouth],[bboxEast],[bboxNorth]

This information matches the Web Map Service (WMS) bounding box specification. If you specify an empty <viewFormat> tag, no information is appended to the query string.

You can also specify a custom set of viewing parameters to add to the query string. If you supply a format string, it is used instead of the BBOX information. If you also want the BBOX information, you need to add those parameters along with the custom parameters. You can use any of the following parameters in your format string (and Google Earth will substitute the appropriate current value at the time it creates the query string):

[lookatLon], [lookatLat] - longitude and latitude of the point that <LookAt> is viewing

[lookatRange], [lookatTilt], [lookatHeading] - values used by the <LookAt> element (see descriptions of <range>, <tilt>, and <heading> in <LookAt>)

[lookatTerrainLon], [lookatTerrainLat], [lookatTerrainAlt] - point on the terrain in degrees/meters that <LookAt> is viewing [cameraLon], [cameraLat], [cameraAlt] - degrees/meters of the eyepoint for the camera

[horizFov], [vertFov] - horizontal, vertical field of view for the camera [horizPixels], [vertPixels] - size in pixels of the 3D viewer

KML Reference - Keyhole Markup Language — Google Developers

<httpQuery>

Appends information to the query string, based on the parameters specified. (Google Earth substitutes the appropriate current value at the time it creates the query string.) The following parameters are supported:

[clientVersion] [kmlVersion] [clientName] [language]

Example

<NetworkLink> <name>NE US Radar</name> <flyToView>1</flyToView> <Link> <href>http://www.example.com/geotiff/NE/MergedReflectivityQComposite.kml</href> <refreshMode>onInterval</refreshMode> <refreshInterval>30</refreshInterval> <viewRefreshMode>onStop</viewRefreshMode> <viewRefreshTime>7</viewRefreshTime> <viewFormat>BBOX=[bboxWest],[bboxSouth],[bboxEast],[bboxNorth];CAMERA=\ [lookatLon],[lookatLat],[lookatRange],[lookatTilt],[lookatHeading];VIEW=\ [horizFov],[vertFov],[horizPixels],[vertPixels],[terrainEnabled]</viewFormat> </Link> </NetworkLink>

Extends

<Object>

Contained By

<ListStyle>

Syntax

<ListStyle id="ID">  <listItemType>check</listItemType>  <bgColor>ffffffff</bgColor>

 <href>...</href>

</ItemIcon>

</ListStyle>

Description

Specifies how a Feature is displayed in the list view. The list view is a hierarchy of containers and children; in Google Earth, this is the Places panel.